TV viewers might have noticed an increase in political advertisements ahead of the November elections this year compared to four years ago. More than 480,000 election ads have run on network and cable TVI this election cycle since 2014 – a 122 percent increase over the same period in 2012, according to a new report.

The Wesleyan Media Project at Wesleyan University in Connecticut, which studies broadcast, network and cable ad spots, estimates that $408 million has been spent on television advertising for the current presidential race. And Republicans have outspent Democrats on TV spots by nearly two-to-one — $270.5 million to $138 million — with much of that coming from super PACs supporting the candidates.

“The reason for the large discrepancy has to do with the involvement of outside groups,” said Erika Franklin Fowler, the project's co-director. “The vast majority of Democratic spots in this cycle have been aired by the candidates themselves,” while outside groups more often air GOP ads, she said.

TV stations are required to offer candidates the same rates on ads as they do for other advertisers, but not so for PACs, whose ads are “sometimes three, four, five times the cost … with the same airtime,” Franklin Fowler said.

Timing is also everything.

“The candidates are often reserving airtime far in advance and that as well will keep costs down,” she said. But outside groups sometimes don’t book ads until closer to airtime.

While the number of Democratic ads fell 6 percent from this point in the 2008 cycle, ads for Republican candidates increased 212 percent compared to 2008, in part the result of a staggering 12,614 percent increase in the volume of ads coming from outside groups, according to the report.

Squandered sums?

Not all super PACs are equal. The committees supporting GOP presidential contenders Jeb Bush and Marco Rubio outspent all other groups on TV spots.

The Right to Rise USA PAC for Bush, a onetime front-runner in the campaign's early days, failed to engender support for its candidate at the polls. Mike Murphy, the PAC’s political strategist, has since come under fire for his management of the committee’s message and donations. The group is estimated to have spent $62.4 million in advertisements.

Conservative Solutions PAC, in support of Rubio, was right behind Right to Rise with $50.9 million in ad expenditures. America Leads, backing Chris Christie, came in a distant third with $14.2 million worth of commercials.\

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Ahead of Ted Cruz’s win in the Wisconsin primary on April 5, stations ran more ads supporting the Texas senator than those favoring Donald Trump — Cruz ads outnumbered those for Trump, 3,652 to 2,073, and over 40 percent of those were anti-Trump (the report did not tally anti-Cruz ads).

Wisconsin saw the most presidential election TV ads from March 16 through May 8, followed by Indiana, New York, and Pennsylvania. More than 17,000 spots were aired in Wisconsin’s five television markets.

But more ads don’t necessarily promise victory. Of the 15,600 presidential ads airing in Indiana’s six TV markets, 7,000 favored Cruz while only 3,000 supported Trump. Trump won the vote by a 53-37 margin.